CHICAGO -- An Illinois teen who was injured in a shooting Friday is believed to have shot himself, officials said.

The 17-year-old boy from Elmwood Park was taken to Loyola Hospital in Maywood, Ill., with a gunshot wound to his left groin area when he reportedly told police he was shot by two men wearing ninja masks.

Police investigated, talked to witnesses and reviewed surveillance but found no evidence of the attack. The boy, who has gang ties, confessed that he was driving in a car and playing with a gun when it discharged in his lap, the Chicago Tribune reported.

Medical personnel said the wound reflected self-infliction and officials are working to determine where the incident occurred to determine which police agency has jurisdiction over the case, according to the Tribune.